Compound mold for casting metal bodies



Dec. 9,1930. ,6. BUHLER COMPOUND I JOLD FOR CASTING METAL BODIES Filed Oct. 29, 1928 Patented Dec. 9, 1930 UNITED STATES GEORG BUHLEB, or VIENNA, AUSTRIA COMPOUND MOLD FOR CASTING METAL BODI ES I Application filed October 29, 1928, Serial No. 315,818, and'ia Germany'Noveniber 4, 1927.

This invention has reference generally to molds and more particularly it relates to a compound mold for casting hollow metal bodies.

The invention has for its object to provide a device of the above character embodying a plurality of chilled molds having smooth outer faces arranged on each so that the same will be more readily apparent from the fol lowing description taken in connection with the accompanying drawings and pointed out in the claims, forming a part of the specification.

A. form of construction of a chill mold according to the invention is illustrated, by way of example, in the accompanying drawings in 30 which:

Fig. 1 shows one single chill mold with core in sectional elevation,

Fig. 2 shows a plan view of a unit comprising eight chill molds.

Fig. 3 shows the lower end and Fig. 4 the upper end of a chill mold.

The chill molds are usually constructed of cast iron castings. 1 is the chill-mold casing with ribs 2. The lower supporting member 3 is rounded at 4 and recessed at 5 for the accommodation of the bottom 6, of the core rod 7. Around the core rod is the body of the core 8. 9 is the centering ring of the mold. The core is held securely by means of the. centering ring 9 and the lower member 6. The metal, which fills up the intermediate space 11 between the core and the walls of the mold is poured in at 10. 12 is the overflow for the molten metal.

A combined unit of eight chill molds is,

shown in Fig. 2. These chill moldsv are secured to one another by screw bolts 17 which pass through the flanges 13 in each chill mold. The ohill molds are smoothed on the whole length of their sides 14 where they abut against one another so that they are adequately connected together to; form a single unit and'that the rates of cooling are equal on allsides of the chill molds. The unitformed by the ei t chill molds is held together by astrong and 18 which lies in the recess between the ribs 2. Below this band there is another weaker band19 around the chill molds. The molds stand on a common base 20 to which they are fixed by meansof screw bolts 21,which pass through thelugs 16 of the chill molds. Only two screw bolts 21 are used, so that the moldshave'allittle-play. All the chill molds are filled through a common funnel. The overflows are so arranged" all directions. -As a matter of fact the loosely stamped middle-portion of the core isgenerallybroken away from the upper hard portion of S8,I1d. I

The perfectly uniform-cooling on all sides is secured by the disposition' of'the ribs, the smoothing of the contact surfacesiof the individual chilllmolds and'the correct choice of the wall thicknesses ofthe molds-. The

wall Ethickness, moreover," must be so' chosen that the castingcan solidify in the correct time. In this connection it is to be observed that the thickness of the mold varies according to the wall thickness of the flanged sockets to be made. The thickness of the wall of the chill mold is millimeters for a the walls are constructed of cast iron and; I

have the thicknesses indicated in the diagram. 7

However, this is essential in order to obtain l a material which will draw well, especially pure bronze draw-holes which can be further drawn to a sufficient extent. In all cases, however, stresses must be prevented; these lead to the formation of cracks and render impossible the further drawing of the drawholes obtained. It has been ascertained that draw-holes cast in the above described chillmolds with the aid of resilient cores have 1 smooth and unbroken skins both inside and 4 outside. Experience shows, however, that this is the necessary requirement for further Working by drawing. "Draw-holes produced according to the present invention maybe drawn out until the walls are A or of the original thickness and sometimes even a smaller fraction thereof. Hitherto this has been quite impossible with tubes of pure bronze. This capability of being further worked is not=a property in drawz-holescast .in sand molds.

WhatZI claim is: .1. A compound-mold for casting metallic bodies comprising a plurality of cylindrical 5 chill molds having-substantially opposed surfaces made smooth 'andrcontactingwithveach other, spaced lugs extending rearwardly from each otthe molds and screw bolts passing throughthe lugs on adjacent molds so as to combine-all of the molds into one unit to facilitate: an casy filling from above" .with

molten materialthrough a commonifunnel.

2. A compound moldas'cla imedainclaim 1, wherein each mold is provided with spaced horizontal ribs formingasubstantialzgroove,

the ribs on thewmoldi aligning "with each other in combination witha band extending about all of the moldszand' lying within'the :groove formed by the ribs, cand meanssfor.

connecting theend-s ofthe band together.

: l GEORG BT'IHLER. 

